Make Kubernetes clusters refreshable

To make it possible to refresh Kubernetes clusters responsible all places that used ClusterDetails[] before now use the KubernetesClustersSupplier directly and call getClusters() on it. This allows people to use implement custom KubernetesClustersSuppliers that fetch the clusters from somewhere and refresh them using whatever mechanism they might need. Signed-off-by: Luna Stadler <luc@spreadshirt.net>
2022-03-24 15:37:33 +01:00
parent e82483f20b
commit 3d45427666
7 changed files with 179 additions and 44 deletions
@@ -0,0 +1,63 @@
+---
+'@backstage/plugin-kubernetes-backend': minor
+---
+
+**BREAKING** Custom cluster suppliers need to cache their getClusters result
+
+To allow custom `KubernetesClustersSupplier` instances to refresh the list of clusters
+the `getClusters` method is now called whenever the list of clusters is needed.
+
+Existing `KubernetesClustersSupplier` implementations will need to ensure that `getClusters`
+can be called frequently and should return a cached result from `getClusters` instead.
+
+For example, here's a simple example of this in `packages/backend/src/plugins/kubernetes.ts`:
+
+```diff
+-import { KubernetesBuilder } from '@backstage/plugin-kubernetes-backend';
+import {
+  ClusterDetails,
+  KubernetesBuilder,
+  KubernetesClustersSupplier,
+} from '@backstage/plugin-kubernetes-backend';
+ import { Router } from 'express';
+ import { PluginEnvironment } from '../types';
+import { Duration } from 'luxon';
+
+export class CustomClustersSupplier implements KubernetesClustersSupplier {
+  private clusterDetails: ClusterDetails[] = [];
+
+  async retrieveClusters() {
+    this.clusterDetails = []; // fetch from somewhere
+  }
+
+  async getClusters(): Promise<ClusterDetails[]> {
+    return this.clusterDetails;
+  }
+}
+
+ export default async function createPlugin(
+   env: PluginEnvironment,
+ ): Promise<Router> {
+-  const { router } = await KubernetesBuilder.createBuilder({
+  const builder = await KubernetesBuilder.createBuilder({
+     logger: env.logger,
+     config: env.config,
+-  }).build();
+  });
+
+  const clusterSupplier = new CustomClustersSupplier();
+  env.scheduler
+    .createScheduledTaskRunner({
+      frequency: Duration.fromObject({ minutes: 60 }),
+      timeout: Duration.fromObject({ minutes: 15 }),
+    })
+    .run({
+      id: 'refresh-kubernetes-clusters',
+      fn: clusterSupplier.retrieveClusters,
+    });
+  builder.setClusterSupplier(clusterSupplier);
+
+  const { router } = await builder.build();
+   return router;
+ }
+```